260 EXPERIMENTS WITH PLANTS 



ing with Fehling's solution (see page 164) if neces- 

 sary, and determine their behavior in this respect. 



The storage of food is extremely advantageous for 

 the plant, not only for the period of rapid growth in 

 the spring but also for the period of flower and fruit. 

 We find various parts of the plant used as storage 

 reservoirs, according to the particular needs of the 

 case. We may say that the problem of storage has 

 been solved by the plant in a great variety of ways. 

 Storage in leaves is seen in seed-leaves, in the scales 

 of bulbs, and in the leaves of succulents (Live -for- 

 ever, Century Plant, etc.). Storage in stems is seen 

 in trees, in Cacti, in tubers of the Potato (examine 

 the Potato and notice the buds, or "eyes," placed in 

 regular fashion and the minute bundles which are 

 more easily seen if the tuber is allowed to stand with 

 the cut surface in eosin until the fluid rises in the 

 bundles; these are indications of its stem nature), 

 the corm of Crocus, the root -stock of Iris, etc. 

 Storage in the root is seen in the Carrot, Turnip, etc. 



In all of the storage organs the form is such as to 

 give a great bulk with little exposed surface, and in 

 very many cases they are sheltered under ground, 

 where they are protected from foes and transpiration 

 is lessened. When above ground they are usually 

 protected from foes by thorns, spines, hairs, etc., or 

 by a bitter or disagi-eeable taste ; to prevent transpira- 

 tion they have much the same devices as leaves: 



